Passwords are used to protect access to various types of buildings, devices and electronic resources such as computers, applications, data files, and online banking sites. Typically, a password system uses an alphanumeric string that is entered on a keyboard. Strong passwords often contain elements such as symbols, capital and lowercase letters, and numbers. These elements that make up strong passwords also make them difficult to remember.
Graphical passwords emerged as an alternative to the standard alphanumeric string password. People tend to remember images with greater accuracy than they remember text.
A common graphical authentication technique is the “passpoints” system. Generally, authentication in this system is represented by a series of click points (points clicked on an image using a computer mouse). During setup of the “passpoints” system, an image is arbitrarily chosen to help the user remember a series of click points. The user clicks on a series of click points in the image, each of the click points being a pixel in the image, and the sequence and location of each click point is stored for comparison with click points entered later by a user trying to gain access to a secured resource. If each click point entered by the user trying to gain access to the secured resource falls within a tolerance region around a corresponding stored click point, then access to the secured resource is granted. A tolerance region around each click point is needed because it is difficult to click on exactly the same pixel each time when entering click points to gain access to the secured resource. A tolerance region may be a circle of a certain radius around the click point. For example, if the click point's x and y coordinates relate to a pixel, then the error tolerance may be a circle with a radius of a certain number of pixels around the click point.
Generally, a computer mouse is used to select the click points within the “passpoints” system. However, many devices today utilize only touch screens as input devices. Touch screens allow a user to make selections or move a cursor by simply touching the touch screen via a finger or stylus. In general, the touch screen recognizes the size, shape and position of a touch on the touch screen and outputs this information to a host device. The host device may be a computer such as a desktop, laptop, handheld or tablet computer, and may be able to recognize a single touch event or multiple touch events at the same time, depending on the type of touch screen.
Touch screens typically include a touch panel and a controller. The touch panel is a clear panel with a touch sensitive surface. The touch panel is positioned in front of a display screen so that the touch sensitive surface covers the viewable area of the display screen. The touch panel registers touch events and sends these signals to the controller. The controller processes these signals into data and sends the data to the host device. Any device that houses a touch screen generally provides an Application Programming Interface (API) that programs can call to utilize the data.
The “passpoints” system described above can also be implemented using a touch screen to select a series of touch points (points touched on an image using a touch screen) instead of a series of click points.
It is known to enhance traditional character based passwords using pressure sensing keyboards to measure the amount of pressure exerted on each key while entering the password. Also, timing between each keystroke has been used to enhance these traditional character based passwords.